xref: /netbsd-src/sys/dev/i2c/adm1026.c (revision 181254a7b1bdde6873432bffef2d2decc4b5c22f)
1 /*-
2  * Copyright (c) 2015 The NetBSD Foundation, Inc.
3  * All rights reserved.
4  *
5  * This code is derived from software contributed to The NetBSD Foundation
6  * by Julian Coleman.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
18  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
19  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
21  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27  * POSSIBILITY OF SUCH DAMAGE.
28  */
29 
30 #include <sys/cdefs.h>
31 __KERNEL_RCSID(0, "$NetBSD: adm1026.c,v 1.8 2020/06/26 10:06:57 martin Exp $");
32 
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/device.h>
36 #include <sys/kernel.h>
37 #include <sys/sysctl.h>
38 
39 #include <dev/sysmon/sysmonvar.h>
40 
41 #include <dev/i2c/i2cvar.h>
42 #include <dev/i2c/adm1026reg.h>
43 
44 /* Voltage/analog sensors descriptions and registers */
45 struct adm1026_volts_info {
46 	const char* desc;
47 	int incr;
48 	uint8_t reg, check_tdm2;
49 };
50 
51 /* Voltage maximums (in mV) from datasheet table 7 divided by 255 increments */
52 static struct adm1026_volts_info adm1026_volts_table[] = {
53 	{ "Vbatt", 15624, ADM1026_VBAT_VAL, 0 },
54 	{ "V3.3 standby", 17345, ADM1026_33VSTBY_VAL, 0 },
55 	{ "V3.3 main", 17345, ADM1026_33VMAIN_VAL, 0 },
56 	{ "V5.0", 26016, ADM1026_50V_VAL, 0 },
57 	{ "Vccp", 11718, ADM1026_VCCP_VAL, 0 },
58 	{ "V+12", 62502, ADM1026_12V_VAL, 0 },
59 	{ "V-12", -62502, ADM1026_N12V_VAL, 0 },
60 	{ "V3.0 0", 11718, ADM1026_AIN_VAL(0), 0 },
61 	{ "V3.0 1", 11718, ADM1026_AIN_VAL(1), 0 },
62 	{ "V3.0 2", 11718, ADM1026_AIN_VAL(2), 0 },
63 	{ "V3.0 3", 11718, ADM1026_AIN_VAL(3), 0 },
64 	{ "V3.0 4", 11718, ADM1026_AIN_VAL(4), 0 },
65 	{ "V3.0 5", 11718, ADM1026_AIN_VAL(5), 0 },
66 	{ "V2.5 0", 9765, ADM1026_AIN_VAL(6), 0 },
67 	{ "V2.5 1", 9765, ADM1026_AIN_VAL(7), 0 },
68 	{ "V2.5 2", 9765, ADM1026_AIN8_VAL, 1 },
69 	{ "V2.5 3", 9765, ADM1026_TDM2_AIN9_VAL, 1 }
70 };
71 
72 /* Maximum number of each type of sensor */
73 #define ADM1026_MAX_FANS	8
74 #define ADM1026_MAX_TEMPS	3
75 #define ADM1026_MAX_VOLTS	(sizeof(adm1026_volts_table) / \
76 				    sizeof (adm1026_volts_table[0]))
77 
78 /* Map sensor to/from sysmon numbers */
79 #define ADM1026_FAN_NUM(x)	(x)
80 #define ADM1026_TEMP_NUM(x)	(x + sc->sc_nfans)
81 #define ADM1026_VOLT_NUM(x)	(x + sc->sc_nfans + sc->sc_ntemps)
82 #define ADM1026_NUM_FAN(x)	(x)
83 #define ADM1026_NUM_TEMP(x)	(x - sc->sc_nfans)
84 #define ADM1026_NUM_VOLT(x)	(x - sc->sc_nfans - sc->sc_ntemps)
85 
86 struct adm1026_softc {
87 	device_t sc_dev;
88 	i2c_tag_t sc_tag;
89 	int sc_address;
90 	bool sc_multi_read;
91 
92 	uint8_t sc_rev, sc_cfg[2];
93 	int sc_nfans, sc_ntemps;	/* Map sysmon numbers to sensors */
94 	int sc_fandiv[ADM1026_MAX_FANS], sc_temp_off[ADM1026_MAX_TEMPS];
95 	struct sysmon_envsys *sc_sme;
96 	envsys_data_t sc_sensor[ADM1026_MAX_FANS + ADM1026_MAX_TEMPS +
97 	    ADM1026_MAX_VOLTS];
98 };
99 
100 static int adm1026_match(device_t, cfdata_t, void *);
101 static int adm1026_ident(i2c_tag_t, i2c_addr_t, int, uint8_t*);
102 static void adm1026_attach(device_t, device_t, void *);
103 static int adm1026_detach(device_t, int);
104 bool adm1026_pmf_suspend(device_t, const pmf_qual_t *);
105 bool adm1026_pmf_resume(device_t, const pmf_qual_t *);
106 
107 static void adm1026_setup_fans(struct adm1026_softc *sc, int div2_val);
108 static void adm1026_setup_temps(struct adm1026_softc *sc);
109 static void adm1026_setup_volts(struct adm1026_softc *sc);
110 
111 void adm1026_refresh(struct sysmon_envsys *sme, envsys_data_t *edata);
112 static void adm1026_read_fan(struct adm1026_softc *sc, envsys_data_t *edata);
113 static void adm1026_read_temp(struct adm1026_softc *sc, envsys_data_t *edata);
114 static void adm1026_read_volt(struct adm1026_softc *sc, envsys_data_t *edata);
115 
116 static int adm1026_read_reg_int(i2c_tag_t, i2c_addr_t,
117     uint8_t reg, bool multi_read, uint8_t *val);
118 static int adm1026_write_reg(struct adm1026_softc *sc,
119     uint8_t reg, uint8_t val);
120 
121 static inline int
122 adm1026_read_reg(struct adm1026_softc *sc, uint8_t reg, uint8_t *val)
123 {
124 	return adm1026_read_reg_int(sc->sc_tag, sc->sc_address, reg,
125 	    sc->sc_multi_read, val);
126 }
127 
128 CFATTACH_DECL_NEW(adm1026hm, sizeof(struct adm1026_softc),
129 	adm1026_match, adm1026_attach, adm1026_detach, NULL);
130 
131 static const struct device_compatible_entry compat_data[] = {
132 	{ "i2c-adm1026",		0 },
133 	{ NULL,				0 }
134 };
135 
136 static int
137 adm1026_match(device_t parent, cfdata_t cf, void *aux)
138 {
139 	struct i2c_attach_args *ia = aux;
140 	int match_result;
141 	uint8_t rev;
142 
143 	if (iic_use_direct_match(ia, cf, compat_data, &match_result))
144 		return match_result;
145 
146 	if (ia->ia_addr == ADM1026_ADDR1
147 	    && adm1026_ident(ia->ia_tag, ia->ia_addr, 1, &rev))
148 		return I2C_MATCH_ADDRESS_AND_PROBE;
149 
150 	return 0;
151 }
152 
153 static int
154 adm1026_ident(i2c_tag_t tag, i2c_addr_t addr, int probe_only, uint8_t *rev)
155 {
156 	uint8_t val;
157 	int err;
158 
159 	/* Manufacturer ID and revision/stepping */
160 	err = adm1026_read_reg_int(tag, addr, ADM1026_ID, false, &val);
161 	if (err || val != ADM1026_MANF_ID) {
162 		if (!probe_only)
163 			aprint_verbose("adm1026_ident: "
164 			    "manufacturer ID invalid or missing\n");
165 		return 0;
166 	}
167 	err = adm1026_read_reg_int(tag, addr, ADM1026_REV, false, rev);
168 	if (err || ADM1026_REVISION(*rev) != ADM1026_MANF_REV) {
169 		if (!probe_only)
170 			aprint_verbose("adm1026_ident: "
171 			    "manufacturer revision invalid or missing\n");
172 		return 0;
173 	}
174 	return 1;
175 }
176 
177 static void
178 adm1026_attach(device_t parent, device_t self, void *aux)
179 {
180 	struct adm1026_softc *sc = device_private(self);
181 	struct i2c_attach_args *ia = aux;
182 	prop_dictionary_t props = device_properties(self);
183 	uint8_t val, fan_div2;
184 	int err, div2_val;
185 
186 	sc->sc_tag = ia->ia_tag;
187 	sc->sc_address = ia->ia_addr;
188 	sc->sc_dev = self;
189 
190 	sc->sc_multi_read = false;
191 	prop_dictionary_get_bool(props, "multi_read", &sc->sc_multi_read);
192 	if (prop_dictionary_get_uint8(props, "fan_div2", &fan_div2) != 0)
193 		div2_val = fan_div2;
194 	else
195 		div2_val = -1;
196 
197 	(void) adm1026_ident(sc->sc_tag, sc->sc_address, 0, &sc->sc_rev);
198 	aprint_normal(": ADM1026 hardware monitor: rev. 0x%x, step. 0x%x\n",
199 	    ADM1026_REVISION(sc->sc_rev), ADM1026_STEPPING(sc->sc_rev));
200 
201 	/*
202 	 * Start monitoring if not already monitoring.
203 	 * Wait 1.8s for the fan readings to stabilise.
204 	 */
205 	if ((err = adm1026_read_reg(sc, ADM1026_CONF1, &val)) != 0) {
206 		aprint_error_dev(sc->sc_dev, ": unable to read conf1\n");
207 		return;
208 	}
209 	if (!(val & ADM1026_CONF1_MONITOR)) {
210 		aprint_normal_dev(sc->sc_dev,
211 		    ": starting monitoring, waiting 1.8s for readings\n");
212 		val |= ADM1026_CONF1_MONITOR;
213 		if ((err = adm1026_write_reg(sc, ADM1026_CONF1, val)) != 0) {
214 			aprint_error_dev(sc->sc_dev,
215 			    ": unable to write conf1\n");
216 			return;
217 		}
218 		delay(1800000);
219 	}
220 	sc->sc_cfg[0] = val;
221 
222 	sc->sc_sme = sysmon_envsys_create();
223 	sc->sc_nfans = 0;
224 	adm1026_setup_fans(sc, div2_val);
225 	sc->sc_ntemps = 0;
226 	adm1026_setup_temps(sc);
227 	adm1026_setup_volts(sc);
228 	aprint_normal_dev(self, "%d fans, %d temperatures, %d voltages\n",
229 	    sc->sc_nfans, sc->sc_ntemps, sc->sc_ntemps == 3 ? 15 : 17);
230 
231         sc->sc_sme->sme_name = device_xname(self);
232         sc->sc_sme->sme_cookie = sc;
233         sc->sc_sme->sme_refresh = adm1026_refresh;
234 	if (sysmon_envsys_register(sc->sc_sme)) {
235 		aprint_error_dev(self,
236 		    "unable to register with sysmon\n");
237 		sysmon_envsys_destroy(sc->sc_sme);
238 		return;
239 	}
240 
241 	if (!pmf_device_register(self, adm1026_pmf_suspend, adm1026_pmf_resume))
242 		aprint_error_dev(self, "couldn't establish power handler\n");
243 
244 	return;
245 }
246 
247 /*
248  * We could stop (suspend/detach) and restart (resume) monitoring,
249  * but we don't do that because some machines have separate
250  * management hardware which can read the sensors.
251  */
252 bool
253 adm1026_pmf_suspend(device_t dev, const pmf_qual_t *qual)
254 {
255 	return true;
256 }
257 
258 bool
259 adm1026_pmf_resume(device_t dev, const pmf_qual_t *qual)
260 {
261 	return true;
262 }
263 
264 static int
265 adm1026_detach(device_t self, int flags)
266 {
267 	struct adm1026_softc *sc = device_private(self);
268 
269 	pmf_device_deregister(self);
270 
271 	sysmon_envsys_unregister(sc->sc_sme);
272 	sc->sc_sme = NULL;
273 
274 	return 0;
275 }
276 
277 static void
278 adm1026_setup_fans(struct adm1026_softc *sc, int div2_val)
279 {
280 	int i, err = 0;
281 	uint8_t div1, div2;
282 
283 	/* Read fan-related registers (configuration and divisors) */
284 	if ((err = adm1026_read_reg(sc, ADM1026_CONF2, &sc->sc_cfg[1])) != 0) {
285 		aprint_error_dev(sc->sc_dev, "unable to read conf2\n");
286 		return;
287 	}
288 	if ((err = adm1026_read_reg(sc, ADM1026_FAN_DIV1, &div1)) != 0) {
289 		aprint_error_dev(sc->sc_dev, "unable to read fan_div1\n");
290 		return;
291 	}
292 	sc->sc_fandiv[0] = 1 << ADM1026_FAN0_DIV(div1);
293 	sc->sc_fandiv[1] = 1 << ADM1026_FAN1_DIV(div1);
294 	sc->sc_fandiv[2] = 1 << ADM1026_FAN2_DIV(div1);
295 	sc->sc_fandiv[3] = 1 << ADM1026_FAN3_DIV(div1);
296 	if (div2_val < 0) {
297 		if ((err =
298 		    adm1026_read_reg(sc, ADM1026_FAN_DIV2, &div2)) != 0) {
299 			aprint_error_dev(sc->sc_dev,
300 			    "unable to read fan_div2\n");
301 			return;
302 		}
303 	} else
304 		div2 = div2_val;
305 	sc->sc_fandiv[4] = 1 << ADM1026_FAN4_DIV(div2);
306 	sc->sc_fandiv[5] = 1 << ADM1026_FAN5_DIV(div2);
307 	sc->sc_fandiv[6] = 1 << ADM1026_FAN6_DIV(div2);
308 	sc->sc_fandiv[7] = 1 << ADM1026_FAN7_DIV(div2);
309 
310 	for (i = 0; i < ADM1026_MAX_FANS; i++) {
311 		sc->sc_sensor[ADM1026_FAN_NUM(i)].state = ENVSYS_SINVALID;
312 		/* Check configuration2 register to see which pins are fans. */
313 		if (ADM1026_PIN_IS_FAN(sc->sc_cfg[1], i)) {
314 			sc->sc_sensor[ADM1026_FAN_NUM(i)].units =
315 			    ENVSYS_SFANRPM;
316 			snprintf(sc->sc_sensor[ADM1026_FAN_NUM(i)].desc,
317 			    sizeof(sc->sc_sensor[ADM1026_FAN_NUM(i)].desc),
318 			    "fan %d", ADM1026_FAN_NUM(i));
319 			sc->sc_nfans++;
320 			if (sysmon_envsys_sensor_attach(
321 			    sc->sc_sme, &sc->sc_sensor[ADM1026_FAN_NUM(i)])) {
322 				sysmon_envsys_destroy(sc->sc_sme);
323 				aprint_error_dev(sc->sc_dev,
324 				    "unable to attach fan %d at sysmon\n", i);
325 				return;
326 			}
327 		}
328 	}
329 }
330 
331 static void
332 adm1026_setup_temps(struct adm1026_softc *sc)
333 {
334 	int i;
335 	uint8_t val;
336 
337 	/* Temperature offsets */
338 	if (adm1026_read_reg(sc, ADM1026_INT_TEMP_OFF, &val)
339 	    != 0) {
340 		aprint_error_dev(sc->sc_dev, "unable to read int temp. off.\n");
341 		return;
342 	}
343 	if (val & 0x80)
344 		sc->sc_temp_off[0] = 0 - 1000000 * (val & 0x7f);
345 	else
346 		sc->sc_temp_off[0] = 1000000 * (val & 0x7f);
347 	if (adm1026_read_reg(sc, ADM1026_TDM1_OFF, &val) != 0) {
348 		aprint_error_dev(sc->sc_dev, "unable to read tdm1 off.\n");
349 		return;
350 	}
351 	if (val & 0x80)
352 		sc->sc_temp_off[1] = 0 - 1000000 * (val & 0x7f);
353 	else
354 		sc->sc_temp_off[1] = 1000000 * (val & 0x7f);
355 	if (adm1026_read_reg(sc, ADM1026_TDM2_OFF, &val) != 0) {
356 		aprint_error_dev(sc->sc_dev, "unable to read tdm2 off.\n");
357 		return;
358 	}
359 	if (val & 0x80)
360 		sc->sc_temp_off[2] = 0 - 1000000 * (val & 0x7f);
361 	else
362 		sc->sc_temp_off[2] = 1000000 * (val & 0x7f);
363 
364 	strlcpy(sc->sc_sensor[ADM1026_TEMP_NUM(0)].desc, "internal",
365 	    sizeof(sc->sc_sensor[ADM1026_TEMP_NUM(0)].desc));
366 	strlcpy(sc->sc_sensor[ADM1026_TEMP_NUM(1)].desc, "external 1",
367 	    sizeof(sc->sc_sensor[ADM1026_TEMP_NUM(1)].desc));
368 	strlcpy(sc->sc_sensor[ADM1026_TEMP_NUM(2)].desc, "external 2",
369 	    sizeof(sc->sc_sensor[ADM1026_TEMP_NUM(2)].desc));
370 	for (i = 0; i < ADM1026_MAX_TEMPS; i++) {
371 		/* Check configuration1 register to see if TDM2 is configured */
372 		if (i == 2 && !ADM1026_PIN_IS_TDM2(sc->sc_cfg[0]))
373 			continue;
374 		sc->sc_sensor[ADM1026_TEMP_NUM(i)].units = ENVSYS_STEMP;
375 		sc->sc_sensor[ADM1026_TEMP_NUM(i)].state = ENVSYS_SINVALID;
376 		sc->sc_ntemps++;
377 		if (sysmon_envsys_sensor_attach(
378 		    sc->sc_sme, &sc->sc_sensor[ADM1026_TEMP_NUM(i)])) {
379 			sysmon_envsys_destroy(sc->sc_sme);
380 			aprint_error_dev(sc->sc_dev,
381 			    "unable to attach temp %d at sysmon\n", i);
382 			return;
383 		}
384 	}
385 }
386 
387 static void
388 adm1026_setup_volts(struct adm1026_softc *sc)
389 {
390 	int i;
391 
392 	for (i = 0; i < ADM1026_MAX_VOLTS; i++) {
393 		/* Check configuration1 register to see if TDM2 is configured */
394 		if (adm1026_volts_table[i].check_tdm2 &&
395 		    ADM1026_PIN_IS_TDM2(sc->sc_cfg[0]))
396 			continue;
397 		strlcpy(sc->sc_sensor[ADM1026_VOLT_NUM(i)].desc,
398 		    adm1026_volts_table[i].desc,
399 		    sizeof(sc->sc_sensor[ADM1026_VOLT_NUM(i)].desc));
400 		sc->sc_sensor[ADM1026_VOLT_NUM(i)].units = ENVSYS_SVOLTS_DC;
401 		sc->sc_sensor[ADM1026_VOLT_NUM(i)].state = ENVSYS_SINVALID;
402 		if (sysmon_envsys_sensor_attach(
403 		    sc->sc_sme, &sc->sc_sensor[ADM1026_VOLT_NUM(i)])) {
404 			sysmon_envsys_destroy(sc->sc_sme);
405 			aprint_error_dev(sc->sc_dev,
406 			    "unable to attach volts %d at sysmon\n", i);
407 			return;
408 		}
409 	}
410 }
411 
412 void
413 adm1026_refresh(struct sysmon_envsys *sme, envsys_data_t *edata)
414 {
415 	struct adm1026_softc *sc = sme->sme_cookie;
416 
417 	if (edata->sensor < sc->sc_nfans)
418 		adm1026_read_fan(sc, edata);
419 	else if (edata->sensor < sc->sc_nfans + sc->sc_ntemps)
420 		adm1026_read_temp(sc, edata);
421 	else
422 		adm1026_read_volt(sc, edata);
423 }
424 
425 static void
426 adm1026_read_fan(struct adm1026_softc *sc, envsys_data_t *edata)
427 {
428 	int fan = ADM1026_NUM_FAN(edata->sensor);
429 	int err;
430 	uint8_t	val;
431 
432 	if ((err = adm1026_read_reg(sc, ADM1026_FAN_VAL(fan), &val)) != 0) {
433 		edata->state = ENVSYS_SINVALID;
434 		return;
435 	}
436 	if (val == 0xff || val == 0x00)	/* Fan missing or stopped */
437 		edata->value_cur = 0;
438 	else
439 		edata->value_cur = 1350000 / (val * sc->sc_fandiv[fan]);
440 	edata->state = ENVSYS_SVALID;
441 }
442 
443 static void
444 adm1026_read_temp(struct adm1026_softc *sc, envsys_data_t *edata)
445 {
446 	int temp = ADM1026_NUM_TEMP(edata->sensor);
447 	int err;
448 	uint8_t	val;
449 
450 	if (temp == 0)
451 		err = adm1026_read_reg(sc, ADM1026_INT_TEMP_VAL, &val);
452 	else if (temp == 1)
453 		err = adm1026_read_reg(sc, ADM1026_TDM1_VAL, &val);
454 	else
455 		err = adm1026_read_reg(sc, ADM1026_TDM2_AIN9_VAL, &val);
456 	if (err) {
457 		edata->state = ENVSYS_SINVALID;
458 		return;
459 	}
460 
461 	if (val & 0x80)	/* Negative temperature */
462 		edata->value_cur = 273150000 - sc->sc_temp_off[temp] -
463 		    1000000 * (val & 0x7f);
464 	else		/* Positive temperature */
465 		edata->value_cur = 273150000 - sc->sc_temp_off[temp] +
466 		    1000000 * val;
467 	edata->state = ENVSYS_SVALID;
468 }
469 
470 static void
471 adm1026_read_volt(struct adm1026_softc *sc, envsys_data_t *edata)
472 {
473 	int volt = ADM1026_NUM_VOLT(edata->sensor);
474 	int err;
475 	uint8_t	val;
476 
477 	err = adm1026_read_reg(sc, adm1026_volts_table[volt].reg, &val);
478 	if (err) {
479 		edata->state = ENVSYS_SINVALID;
480 		return;
481 	}
482 	/* Vbatt is not valid for < 1.5V */
483 	if (volt == 0 && val < 0x60)
484 		edata->state = ENVSYS_SINVALID;
485 	edata->value_cur = (int) val * adm1026_volts_table[volt].incr;
486 	edata->state = ENVSYS_SVALID;
487 }
488 
489 static int
490 adm1026_read_reg_int(i2c_tag_t tag, i2c_addr_t addr, uint8_t reg,
491     bool multi_read, uint8_t *val)
492 {
493 #define ADM1026_READ_RETRIES	5
494 	int i, j, err = 0;
495 	uint8_t creg, cval, tmp[ADM1026_READ_RETRIES + 1];
496 
497 	if ((err = iic_acquire_bus(tag, 0)) != 0)
498 		return err;
499 	/* Standard ADM1026 */
500 	if (multi_read == false) {
501 		err = iic_exec(tag, I2C_OP_READ_WITH_STOP,
502 		    addr, &reg, 1, val, 1, 0);
503 	/*
504 	 * The ADM1026 found in some Sun machines sometimes reads bogus values.
505 	 * We'll read at least twice and check that we get (nearly) the same
506 	 * value.  If not, we'll read another register and then re-read the
507 	 * first.
508 	 */
509 	} else {
510 		if (reg == ADM1026_CONF1)
511 			creg = ADM1026_CONF2;
512 		else
513 			creg = ADM1026_CONF1;
514 		if ((err = iic_exec(tag, I2C_OP_READ_WITH_STOP,
515 		    addr, &reg, 1, &tmp[0], 1, 0)) != 0) {
516 			iic_release_bus(tag, 0);
517 			return err;
518 		}
519 		for (i = 1; i <= ADM1026_READ_RETRIES; i++) {
520 			if ((err = iic_exec(tag, I2C_OP_READ_WITH_STOP,
521 			    addr, &reg, 1, &tmp[i], 1, 0)) != 0)
522 				break;
523 			for (j = 0; j < i; j++)
524 				if (abs(tmp[j] - tmp[i]) < 3) {
525 					*val = tmp[i];
526 					iic_release_bus(tag, 0);
527 					return 0;
528 				}
529 			if ((err = iic_exec(tag, I2C_OP_READ_WITH_STOP,
530 			    addr, &creg, 1, &cval, 1, 0)) != 0)
531 				break;
532 			err = -1;	/* Return error if we don't match. */
533 		}
534 	}
535 	iic_release_bus(tag, 0);
536 	return err;
537 }
538 
539 static int
540 adm1026_write_reg(struct adm1026_softc *sc, uint8_t reg, uint8_t val)
541 {
542 	int err = 0;
543 
544 	if ((err = iic_acquire_bus(sc->sc_tag, 0)) != 0)
545 		return err;
546 	err = iic_exec(sc->sc_tag, I2C_OP_WRITE_WITH_STOP, sc->sc_address,
547 	    &reg, 1, &val, 1, 0);
548 	iic_release_bus(sc->sc_tag, 0);
549 	return err;
550 }
551